Urotensin II (114-124), human, an 11-amino acid residue peptide, is a potent vasoconstrictor and agonist for the orphan receptor GPR14. IC50 & Target: GPR14^[1] In Vitro: Human Urotensin II (U-II) binds to recombinant human GPR14 with high affinity, and the binding is functionally coupled to calcium mobilization. Human Urotensin II induces concentration-dependent increases in intracellular calcium in a HEK-293 cell line expressing human GPR14 (EC₅₀=0:62±0.17 nM, n=6)^[1]. In Vivo: Human Urotensin II (U-II) markedly increases total peripheral resistance in anaesthetized non-human primates, a response associated with profound cardiac contractile dysfunction^[1].